Hot-pressing sintered BN-SiO2 composite ceramics with excellent thermal conductivity and dielectric properties for high frequency substrate

High thermal conductivity and low dielectric constant are the more and more important properties for high-frequency substrate materials to enhance their heat radiation and reduce signal delay. In this work, a series of BN-SiO2 composite ceramics for high frequency application were successfully synthesized by hot-pressing sintering method. And their structures, thermal and dielectric properties were systematically studied. According to the results, the excellent thermal conductivity with low dielectric constant and low dielectric loss has been obtained in the BN-SiO2 ceramic. Compared to the pure SiO2, the sample with 50 wt% BN addition sintered at 1650 ℃ exhibited excellent physical properties, including a high thermal conductivity of 6.75 W/m K which is almost five times higher than that of pure SiO2 and a low dielectric constant of 3.73. The achieved high thermal conductivity and appropriate dielectric property of the BN-SiO2 composite ceramic make it a promising candidate for high-frequency substrate application.